Page 9 - ME News 2021 from the Penn State Department of Mechanical Engineering

Research Highlights
Innovative
batteries put
flying cars on
on
the horizon
By A’ndrea Elyse Messer
Jet packs robot maids and flying cars were all promises for the 21st century We got mechanized autonomous vacuum cleaners instead MENews 2021
9
Now a a a a a team of Penn State researchers are exploring the requirements for electric vertical takeoff and and and landing or eVTOL vehicles and and and and designing and and testing potential battery power sources “I think flying cars have the potential to eliminate a a a a a a a a lot of time and and increase productivity and and open the sky corridors to transportation ” said Chao-Yang Wang William E E Diefender Chair
of of Mechanical Engineering and director of of the Electrochemical Engine Engine Center at at Penn State “But electric vertical takeoff and and landing vehicles are very challenging technology for the batteries ” The researchers defined the technical requirements for flying car batteries and reported on
a a a a a prototype battery in Joule “Batteries for flying cars need very high energy density so so that you can stay in in the the air
” Wang said “And they also need very high power during take-off
and and and landing It requires a a a a a lot of power to go vertically up and and and down ” Wang notes that that the batteries will also need to be be rapidly recharged so so that that there could be be high revenue during rush hours He sees these vehicles having frequent take-offs and and and and landings and and and and recharging quickly and and and and often “Commercially I would expect these vehicles to to make fifteen trips twice a a a a day during rush hour to to justify the the cost of the the vehicles ” Wang said “The first use will probably be from a a a a a a a city to to an an airport carrying three to to four people about fifty miles ” The researchers experimentally tested two energy-dense lithium-ion batteries that can recharge with enough energy energy for a a a a a a fifty-mile eVTOL trip in in in five to ten minutes These batteries could sustain more than 2 000 fast-charges over their lifetime Wang and his team used technology they have been working on
for electric vehicle batteries The key is to heat
the the battery to allow rapid charging without the the the formation of dangerous lithium spikes that that damage the the battery It turns out that that this heating also allows rapid discharge of of the the energy held in in the the battery to allow for takeoffs and and landings The researchers heat
the batteries by incorporating a a a a a a a a nickel foil that brings the battery rapidly to 140 degrees Fahrenheit “I hope that the work we have done in this paper will give people a a a a a a a solid idea that we we don’t need another twenty years to finally get these vehicles ” Wang said “I believe we we have demonstrated that the eVTOL is commercially viable ” Also working on
this project were Xiao-Guang Yang and Shanhai Ge both assistant research professors in in in mechanical mechanical engineering and Teng
Liu doctoral student in in in in in mechanical mechanical engineering all at at at Penn State State and Eric Roundtree EC Power State State College Pennsylvania